Multilayer ceramic capacitor

ABSTRACT

A multilayer ceramic capacitor includes a capacitor main body including a multilayer body and external electrodes, the multilayer body including dielectric layers and internal electrode layers stacked alternately, each of the external electrodes being provided on an end surface in a length direction of the multilayer body and being connected to the internal electrode layers, and two interposers on one surface in a stacking direction of the capacitor main body and spaced apart from each other in the length direction, the interposers including bonding surfaces bondable to the one surface of the capacitor main body and including inner edge portions which are opposite to each other and each having a length longer than a length in a width direction of the multilayer body.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication No. 2021-083829 filed on May 18, 2021. The entire contentsof this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a multilayer ceramic capacitor.

2. Description of the Related Art

Recently, a large-capacitance and small-size multilayer ceramiccapacitor has been demanded. Such a multilayer ceramic capacitorincludes an inner layer portion in which dielectric layers made of aferroelectric material having relatively high dielectric constant andinternal electrodes are alternately stacked.

Furthermore, the dielectric layers as outer layer portions are disposedat the upper and lower portions of the inner layer portion. As a result,a rectangular parallelepiped-shape multilayer body is provided.Furthermore, the external electrodes are provided on both end surfacesin the length direction of the multilayer body, such that the capacitormain body is provided.

Furthermore, in order to reduce or prevent the generation of so-called“acoustic noise”, a multilayer ceramic capacitor having interposers isknown (see PCT International Publication No. WO2015/098990). Theseinterposers are located on one side of the capacitor main body. This oneside of the capacitor main body is a side on which the substrate ismounted.

SUMMARY OF THE INVENTION

However, sometimes stress due to bending or the like is applied to thesubstrate on which the multilayer ceramic capacitor is mounted. In thatcase, the inner edge portion of the bonding surface of the interposer tobe bonded to the capacitor main body presses the capacitor main body. Asa result, stress is concentrated in the contact portion. Therefore,there is a possibility of cracks occurring in the capacitor main body.

Preferred embodiments of the present invention provide multilayerceramic capacitors each capable of reducing stress concentration on acapacitor main body caused by contact with an interposer.

A preferred embodiment of the present invention provides a multilayerceramic capacitor including a capacitor main body including a multilayerbody and external electrodes, the multilayer body including dielectriclayers and internal electrode layers stacked alternately, each of theexternal electrodes being provided on an end surface in a lengthdirection of the multilayer body and being connected to the internalelectrode layers, and two interposers provided on one surface in astacking direction of the capacitor main body and spaced apart from eachother in the length direction, the two interposers further includingbonding surfaces to be bonded to the one surface of the capacitor mainbody, the bonding surfaces including inner edge portions which areopposite to each other, the inner edge portions each having a lengthlonger than a length in a width direction of the multilayer body.

According to preferred embodiments of the present invention, it ispossible to provide multilayer ceramic capacitors each capable ofreducing stress concentration on the capacitor main body caused bycontact with the interposer.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a multilayer ceramic capacitor1 according to a preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 ,of the multilayer ceramic capacitor 1.

FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1, of the multilayer ceramic capacitor 1.

FIG. 4 is a view of the multilayer ceramic capacitor 1 as seen from aninterposer 4.

FIG. 5 provides a flowchart showing a method of manufacturing themultilayer ceramic capacitor 1.

FIG. 6A is a diagram illustrating a capacitor main body manufacturingstep S1.

FIG. 6B is a diagram illustrating a capacitor main body manufacturingstep S1.

FIG. 6C is a diagram illustrating a capacitor main body manufacturingstep S1.

FIG. 6D is a diagram illustrating a capacitor main body manufacturingstep S1.

FIG. 7A is a diagram for explaining an interposer providing step S2.

FIG. 7B is a diagram for explaining an interposer providing step S2.

FIG. 7C is a diagram for explaining an interposer providing step S2.

FIG. 8 is a view of a multilayer ceramic capacitor la of a firstmodification example as seen from a mounting surface AI2.

FIG. 9A is a view of a multilayer ceramic capacitor 1 b of a secondmodification example as seen from the mounting surface AI2.

FIG. 9B is a view of a multilayer ceramic capacitor 1 b of a secondmodification example as seen from the mounting surface AI2.

FIG. 10A is a view of a multilayer ceramic capacitor 1 c of a thirdmodification example as seen from the mounting surface AI2.

FIG. 10B is a view of a multilayer ceramic capacitor 1 c of a thirdmodification example as seen from the mounting surface AI2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, multilayer ceramic capacitors according to preferredembodiments of the present invention will be described. FIG. 1 is aschematic perspective view of a multilayer ceramic capacitor 1 accordingto a preferred embodiment of the present invention. FIG. 2 is across-sectional view taken along the line II-II in FIG. 1 , of themultilayer ceramic capacitor 1. FIG. 3 is a cross-sectional view takenalong the line III-III in FIG. 1 , of the multilayer ceramic capacitor1.

The multilayer ceramic capacitor 1 has a substantially rectangularparallelepiped shape. The multilayer ceramic capacitor 1 includes acapacitor main body 1A and interposers 4. The capacitor main body 1Aincludes a multilayer body 2, and a pair of external electrodes 3provided at both ends of the multilayer body 2. The interposers 4 areattached to the capacitor main body 1A. The multilayer body 2 alsoincludes an inner layer portion 11. The inner layer portion 11 includesa plurality of sets of dielectric layers 14 and internal electrodelayers 15.

In the following description, the term representing the direction of themultilayer ceramic capacitor 1 is defined herein. In the multilayerceramic capacitor 1, the direction in which the pair of externalelectrodes 3 are provided is defined as the length direction L. Thedirection in which the dielectric layer 14 and the internal electrodelayer 15 are laminated (stacked) is defined as the stacking direction T.The direction intersecting both the length direction L and the stackingdirection T is defined as the width direction W. It should be notedthat, in the present preferred embodiment, the width direction W isorthogonal or substantially orthogonal to both the length direction Land the stacking (lamination) direction T.

Outer Surface of Multilayer Body 2

Furthermore, a pair of outer surfaces among the six outer surfaces ofthe multilayer body 2 which are opposite to each other in the stackingdirection T are defined as a first main surface AS1 of the multilayerbody and a second main surface AS2 of the multilayer body. A pair ofouter surfaces among the six outer surfaces of the multilayer body 2which are opposite to each other in the width direction W are defined asa first side surface BS1 of the multilayer body and a second sidesurface BS2 of the multilayer body. Furthermore, a pair of outersurfaces among the six outer surfaces of the multilayer body 2 which areopposite to each other in the length direction L are defined as a firstend surface CS1 of the multilayer body and a second end surface CS2 ofthe multilayer body.

When it is not necessary to distinguish between the first main surfaceAS1 of the multilayer body and the second main surface AS2 of themultilayer body, they are collectively defined as the main surface AS ofthe multilayer body. When it is not necessary to distinguish the firstside surface BS1 of the multilayer body and the second side surface BS2of the multilayer body, they are collectively defined as the multilayerbody side surface BS. Furthermore, when it is not necessary todistinguish the first end surface CS1 of the multilayer body and thesecond end surface CS2 of the multilayer body, they are collectivelydefined as the multilayer body end surface CS.

Outer Surface of Capacitor Main Body 1A

Furthermore, a pair of outer surfaces among the six outer surfaces ofthe capacitor main body 1A which are opposite to each other in thestacking direction T are defined as a first main surface AC1 of the mainbody and a second main surface AC2 of the main body. A pair of outersurfaces among the six outer surfaces of the capacitor main body 1Awhich are opposite to each other in the width direction W are defined asa first side surface BC1 of the main body and a second side surface BC2of the main body. Furthermore, a pair of outer surfaces among the sixouter surfaces of the capacitor main body 1A which are opposite to eachother in the length direction L are defined as a first end surface CC1of the main body and a second end surface CC2 of the main body.

When it is not necessary to distinguish between the first main surfaceAC1 of the main body and the second main surface AC2 of the main body,they are collectively defined as the main surface AC of the main body.Furthermore, when it is not necessary to distinguish between the firstside surface BC1 of the main body and the second side surface BC2 of themain body, they are collectively defined as side surfaces BC of the mainbody. Furthermore, when it is not necessary to distinguish between thefirst end surface CC1 of the main body and the second end surface CC2 ofthe main body, they are collectively defined as the end surface CC ofthe main body.

Outer Surface of Interposer 4

FIG. 4 is a view of the multilayer ceramic capacitor 1 of the presentpreferred embodiment as seen from the interposer 4. The interposer 4includes a first interposer 4A and a second interposer 4B. Among thepair of outer surfaces which are opposite to each other in the stackingdirection T among the six outer surfaces of the respective interposers4, an outer surface in the vicinity of the capacitor main body 1A isdefined as a bonding surface AIl. Also, among the pair of outer surfaceswhich are opposite to each other in the stacking direction T among thesix outer surfaces of the respective interposers 4, an outer surface inthe vicinity of the substrate is defined as a mounting surface AI2.

Furthermore, the surfaces of the first interposer 4A and the secondinterposer 4B which face each other in the length direction L aredefined as a facing surface CIA and a facing surface CIB. When it is notnecessary to distinguish between the facing surface CIA and the facingsurface CIB from each other, they are collectively defined as the facingsurface CI.

The bonding surface AI1 of the interposer 4 and the second main surfaceAC2 of the main body of the capacitor main body 1A face each other.

Multilayer Body 2

The dimensions of the multilayer body 2 are not particularly limited.However, it is preferable that the dimensions of the multilayer body 2have a dimension of about 0.2 mm or more and about 10 mm or less in thelength direction L, a dimension of about 0.1 mm or more and about 10 mmor less in the width direction W, and a dimension of about 0.1 mm ormore and about 5 mm or less in the stacking direction T.

The multilayer body 2 includes a multilayer main body 10 and side gapportions 30. The multilayer main body 10 includes an inner layer portion11, and outer layer portions 12. The outer layer portions 12 areprovided on both sides in the stacking direction T of the inner layerportion 11, respectively. The side gap portions 30 are provided on bothsides in the width direction W of the multilayer main body 10.

Inner Layer Portion 11

The inner layer portion 11 includes a plurality of sets of dielectriclayers 14 and internal electrode layers 15. The dielectric layer 14 andthe internal electrode layer 15 are alternately stacked in the stackingdirection T.

The dielectric layer 14 has a thickness of about 0.5 μm or less. Thedielectric layer 14 is made of a ceramic material. Examples of ceramicmaterials include, for example, dielectric ceramics including BaTiO₃ asa main component. Furthermore, a ceramic material obtained by adding atleast one of sub-components such as Mn compounds, Fe compounds, Crcompounds, Co compounds, and Ni compounds to these main components maybe used. It should be noted that the number of dielectric layers 14,including the outer layer portion 12, is preferably 15 sheets or moreand 700 sheets or less.

The internal electrode layer 15 includes a plurality of first internalelectrode layers 15 a and a plurality of second internal electrodelayers 15 b. The first internal electrode layers 15 a and the secondinternal electrode layers 15 b are provided alternately. When it is notnecessary to distinguish between the first internal electrode layer 15 afrom the second internal electrode layer 15 b, they are collectivelydefined as the internal electrode layer 15.

The first internal electrode layer 15 a includes a first opposingportion 152 a and a first extension portion 151 a. The first opposingportion 152 a faces the second internal electrode layer 15 b. The firstextension portion 151 a extends from the first opposing portion 152 atoward the first end surface CS1 of the multilayer body. The end portionof the first extension portion 151 a is exposed on the first end surfaceCS1 of the multilayer body. The end portion of the first extensionportion 151 a is electrically connected to a first external electrode 3a to be described later.

The second internal electrode layer 15 b includes a second opposingportion 152 b and a second extension portion 151 b. The second opposingportion 152 b faces the first internal electrode layer 15 a. The secondextension portion 151 b extends from the second opposing portion 152 btoward the second end surface CS2 of the multilayer body. The end of thesecond extension portion 151 b is electrically connected to the secondexternal electrode 3 b to be described later.

A charge is accumulated in the first opposing portion 152 a of the firstinternal electrode layer 15 a and the second opposing portion 152 b ofthe second internal electrode layer 15 b. As a result, thecharacteristics of the capacitor are realized.

The internal electrode layer 15 is preferably made of a metal materialsuch as Ni, Cu, Ag, Pd, Ag—Pd alloy, and Au. The internal electrodelayer 15 preferably has, for example, a thickness of about 0.5 μm ormore and about 2.0 mm. The number of the internal electrode layers 15 ispreferably 15 or more and 700 or less as the total of the first internalelectrode layer 15 a and the second internal electrode layer 15 b.

Outer Layer Portions 12

The outer layer portions 12 are made of the same material as thedielectric layers 14 of the inner layer portion 11. The outer layerportions 12 preferably have a thickness of, for example, about 20 μm orless. More preferably, the outer layer portions 12 have a thickness ofabout 10 μm or less.

Side Gap Portions 30

The side gap portions 30 each include a first side gap portion 30 a anda second side gap portion 30 b. The first side gap portion 30 a isprovided in the vicinity of the side surface BS of the multilayer bodyof the multilayer main body 10. The second side gap portion 30 b isprovided in the vicinity of the second side surface BS2 of themultilayer body of the multilayer main body 10.

When it is not necessary to distinguish the first side gap portion 30 aand the second side gap portion 30 b from each other, they arecollectively defined as the side gap portion 30.

The side gap portions 30 are each made of a material similar to thedielectric layer 14. The side gap portions 30 each have a thickness of,for example, about 20 μm. The side gap portions 30 each preferably havea thickness of about 10 μm or less.

External Electrodes 3

The external electrodes 3 each include a first external electrode 3 aand a second external electrode 3 b. The first external electrode 3 a isprovided on the first end surface CS1 of the multilayer body. The secondexternal electrode 3 b is provided on the second end surface CS2 of themultilayer body. When it is not necessary to distinguish between thefirst external electrode 3 a and the second external electrode 3 b, theyare collectively defined as the external electrode 3. The externalelectrode 3 covers not only the end surface CS of the multilayer body,but also covers a portion of each of the main surface AS and the sidesurface BS of the multilayer body. The portion of each of the mainsurface AS and the side surface BS of the multilayer body is in thevicinity of the end surface CS.

As described above, the end portion of the first extension portion 151 aof the first internal electrode layer 15 a is exposed on the first endsurface CS1 of the multilayer body, and is electrically connected to thefirst external electrode 3 a. Furthermore, the end portion of the secondextension portion 151 b of the second internal electrode layer 15 b isexposed on the second end surface CS2 of the multilayer body, and iselectrically connected to the second external electrode 3 b. With thisconfiguration, a plurality of capacitor elements are electricallyconnected in parallel between the first external electrode 3 a and thesecond external electrode 3 b.

Interposers 4

The interposers 4 each include a pair of a first interposer 4A and asecond interposer 4B. Hereinafter, when it is not necessary todistinguish between the first interposer 4A and the second interposer4B, they are collectively defined as the interposer 4.

The first interposer 4A is provided in the vicinity of the first endsurface CC1 of the main body on the second main surface AC2 of thecapacitor main body 1A. The first end surface CC1 of the main body isprovided on one side in the length direction L. The second interposer 4Bis provided in the vicinity of the second end surface CC2 of the mainbody on the second main surface AC2 of the capacitor main body 1A. Thesecond end surface CC2 of the main body is provided on the other side inthe length direction L. The first interposer 4A and the secondinterposer 4B are of the same shape and face each other. The firstinterposer 4A and the second interposer 4B are spaced apart from eachother by a predetermined distance.

In the present preferred embodiment, the interposer 4 includes a memberincluding a material containing an intermetallic compound as a maincomponent. The intermetallic compounds include, for example, at leastone high melting point metal selected from Cu and Ni, and Sn as a lowmelting point metal. The interposer 4 includes a single Sn metal apartfrom the intermetallic compound. The Sn metal included in the interposer4 achieves favorable solderability in the interposer 4 when mounting themultilayer ceramic capacitor 1 on the substrate.

However, the material of the interposer 4 according to a preferredembodiment of the present invention is not limited to theabove-described material. The material of the interposer 4 according toa preferred embodiment of the present invention may be other metals. Ifthe conduction between the external electrode 3 and the substrate isensured by solder, etc., the interposer 4 may be made of a materialother than metal.

Shape of Interposer 4

The bonding surface AI1 of the interposer 4 is bonded to the second mainsurface AC2 of the main body of the capacitor main body 1A.

The bonding surface AI1 of the first interposer 4A includes an inneredge portion 42. The bonding surface AI1 of the second interposer 4Bincludes an inner edge portion 42. The inner edge portions 42 face eachother in the length direction L.

The first interposer 4A includes an inner edge portion 42A. The secondinterposer 4B includes an inner edge portion 42B. That is, among theedges of the bonding surface AI1 of the first interposer 4A, the edgeclosest to the second interposer 4B is the inner edge portion 42A.Furthermore, among the edges of the bonding surface AI1 of the secondinterposer 4B, the edge closest to the first interposer 4A is the inneredge portion 42B.

When it is not necessary to distinguish between the inner edge portion42A and the inner edge portion 42B, they are collectively defined as theinner edge portion 42.

As shown in FIG. 4 , the inner edge portion 42 of the interposer 4 ofthe present preferred embodiment is curved in a recessed shape. In thebonding surface AI1 of each interposer 4, the length L2 at the centralportion in the width direction W of the inner edge portion 42 is theshortest. The length L3 of both side regions in the width direction W ofthe inner edge portion 42 is the longest.

It should be noted that the bonding surface AI1 of the interposer 4 inFIG. 4 is not visible. However, the bonding surface AI1 overlaps themounting surface AI2 in FIG. 4 , and has the same shape as the mountingsurface AI2.

Both side regions in the width direction W which have the longest lengthL3 each include not only the end in the width direction W, but also aportion slightly closer to the central portion than the end. In thepresent preferred embodiment, as shown in FIG. 4 , the portion 44 whichis slightly closer to the central portion than the end in the widthdirection W is the longest.

Furthermore, an outer edge portion 43 is disposed on the edge of thebonding surface AI1 opposite to the inner edge portion 42. In thepresent preferred embodiment, the outer edge portion 43 is not curved.The outer edge portion 43 extends linearly in the width direction W.

When defining the length of the multilayer body 2 as L, the differenceL1 between the length L3 of the longest portion and the length L2 of theshortest portion in the bonding surface AI1 is approximately L×0.05L1≤L×0.40. The relationship between the length L2 of the shortestportion and the length L3 of the longest portion in the bonding surfaceAI1 is approximately L2×1.10≤L3≤L2×1.40. Furthermore, the length of theinner edge portion 42 which is curved is longer than the length in thewidth direction W of the multilayer body 2, and the length (width) isabout 1.1W or more and about 2W or less.

In the present preferred embodiment, as shown in FIG. 2 , the interposer4 has a constant or substantially constant LW cross-sectional shaperegardless of the position in the stacking direction T when excludingthe portion where the external electrode 3 is present.

However, the present invention is not limited thereto. If the inner edgeportion 42 is curved, the interposer 4 may have a different profile fromthe inner edge portion 42 in the lower portion in the stacking directionT from the inner edge portion 42 in the drawings.

In the present preferred embodiment, in the bonding surface AI1 of theinterposer 4, even the portion of the shortest length L2 in the lengthdirection L is longer than the length L4 of the portion extending towardthe second main surface AC2 of the main body of the capacitor main body1A in the external electrode 3. Therefore, as shown in FIG. 4 , theexternal electrode 3 is not visible by the inner edge portion 42 of thebonding surface AI1.

Method of Manufacturing Multilayer Ceramic Capacitor

FIG. 5 provides a flowchart showing a method of manufacturing themultilayer ceramic capacitor 1. The method of manufacturing a multilayerceramic capacitor 1 includes a capacitor main body manufacturing stepS1, and an interposer providing step S2.

FIGS. 6A to 6D are diagrams illustrating the capacitor main bodymanufacturing step S1. FIGS. 7A to 7C are diagrams for explaining theinterposer providing step S2.

Capacitor Main Body Manufacturing Step S1

The capacitor main body manufacturing step S1 includes a multilayer bodymanufacturing step S11 and an external electrode forming step S12.

Multilayer Body Manufacturing Step S11

A ceramic slurry includes a ceramic powder, a binder, and a solvent.This ceramic slurry is molded into a sheet form on the carrier filmusing a die coater, gravure coater, micro gravure coater, etc. In thisway, the multilayer ceramic green sheet 101 defining and functioning asa dielectric layer 14 is manufactured.

Then, the conductive paste is printed on the multilayer ceramic greensheet 101 in strips by screen printing, ink jet printing, gravureprinting or the like. In this way, the conductive pattern 102 definingand functioning as the internal electrode layer 15 is printed on thesurface of the multilayer ceramic green sheet 101, such that thematerial sheet 103 is manufactured.

Subsequently, as shown in FIG. 6A, a plurality of material sheets 103are stacked. The plurality of material sheets 103 are provided so thatthe conductive patterns 102 are in a state of facing in the samedirection and being shifted by half pitch in the width direction betweenthe adjacent material sheets 103.

Furthermore, ceramic green sheets 112 for the upper outer layer portionare stacked on both sides of the plurality of laminated material sheets103. The ceramic green sheets 112 for the upper outer layer portionfunction as the outer layer portions 12.

The plurality of laminated material sheets 103 and the ceramic greensheets 112 for the outer layer portions are subjected tothermocompression bonding, to manufacture a mother block 110 shown inFIG. 6B.

Next, the mother block 110 is cut along the cutting line X and thecutting line Y intersecting the cutting line X shown in FIG. 6B tomanufacture a plurality of multilayer bodies 2 shown in FIG. 6C.

External Electrode Forming Step S12

Subsequently, as shown in FIG. 6D, a conductive paste containing aconductive metal and glass is applied to the end surface CS of themultilayer body of the multilayer body 2, and the resulting object isfired to form the external electrodes 3. The external electrodes 3 eachcover not only the end surfaces CS of the multilayer body on the bothsides of the multilayer body 2, but also extend toward the main surfaceAS and the side surface of the multilayer body, and thus cover a portionof the main surface AS of the multilayer body in the vicinity of the endsurface CS of the multilayer body. Through the above steps, thecapacitor main body 1A is manufactured.

Interposer Providing Step S2

A metal material paste defining and functioning as a material of theinterposer is prepared. The metal material paste includes at least onehigh melting point metal selected from Cu and Ni, and Sn as a lowmelting point metal. In addition, a holding plate 40 is prepared. In theholding plate 40, the metal material paste is not bonded under reflowconditions, for example, as in an alumina plate.

As shown in FIG. 7A, a metal material paste is applied onto the holdingplate 40 by a screen printing method, a dispensing method, or the like.As a result, a metal material paste thick film 41 is formed in which thebonding surface AI1, i.e., the inner edge portion 42 is curved.

As shown in FIG. 7B, the capacitor main body 1A is mounted on theholding plate 40 in a posture in which the second main surface AC2 ofthe main body faces the holding plate 40. At this time, the externalelectrodes 3 and the metal material paste thick film 41 of the capacitormain body 1A are aligned. In this manner, the metal material paste thickfilm 41 is attached to the capacitor main body 1A.

In this state, a reflow step is performed. Thus, the metal in the metalmaterial paste thick film 41 produces an intermetallic compound.Furthermore, the metal material paste thick film 41 is cured.Consequently, the interposer 4 in a state of being bonded to thecapacitor main body 1A and the external electrode 3 is formed.

Thereafter, the capacitor main body 1A is separated from the holdingplate 40 with the interposer 4. As a result, the state shown in FIG. 7Cis established.

Through the above steps, the multilayer ceramic capacitor 1 in which theinterposer 4 is attached to the capacitor main body 1A is manufactured.

Effects of Preferred Embodiment

There are cases where stress due to bending or the like is applied tothe substrate on which the multilayer ceramic capacitor 1 is mounted. Atthis time, there is a possibility that the inner edge portion 42 of thebonding surface AI1 of the interposer 4 presses the second main surfaceAC2 of the main body of the capacitor main body 1A.

Here, the ceramic portion of the multilayer body 2 is exposed at theportion where the external electrode 3 of the second main surface AC2 ofthe main body of the capacitor main body 1A is not provided. Thisceramic portion is pressed by the inner edge portion 42 and the stressis concentrated in the ceramic portion, as a result of which cracks mayoccur.

However, in the present preferred embodiment, the inner edge portion 42of the bonding surface AI1 of the interposer 4 is curved. That is, thelength of the inner edge portion 42 is longer than the length in thewidth direction W of the multilayer body 2.

Therefore, the concentration of stress on the second main surface AC2 ofthe main body of the capacitor main body 1A caused by contact with theinterposer 4 is alleviated. Therefore, it is possible to reduce thepossibility of cracking of the capacitor main body 1A.

Preferred embodiments of the present invention have been describedabove. However, the present invention is not limited thereto. Variousmodifications are possible within the scope of the present invention.

(1) FIRST MODIFICATION EXAMPLE

FIG. 8 is a view of the multilayer ceramic capacitor la of the firstmodification example as seen from the mounting surface AI2. In thefollowing description, the same portions as those of the first preferredembodiment are denoted by the same reference numerals.

In the present preferred embodiment, in the bonding surface AI1 of theinterposer 4, the shortest length L2 in the length direction L is longerthan the length L4 extending toward the second main surface AC2 of themain body of the capacitor main body lA in the external electrode 3.

However, the present invention is not limited thereto. As shown in FIG.8 , in the bonding surface AI1 of the interposer 4, the shortest lengthL2 in the length direction L may be shorter than the length L4 of theportion extending toward the second main surface AC2 of the main body ofthe capacitor main body lA in the external electrode 3.

In this case, as shown in FIG. 8 , the external electrode 3 is exposedfrom the inner edge portion 42 of the bonding surface AI1.

Also in the first modification example, similarly to the above-describedpreferred embodiments, the length of the inner edge portion 42 is longerthan the length in the width direction W of the multilayer body 2.Therefore, the concentration of stress caused by contact with theinterposer 4 onto the second main surface AC2 of the main body of thecapacitor main body 1A is alleviated.

Therefore, it is possible to reduce the possibility of cracking of thecapacitor main body 1A.

(2) SECOND MODIFICATION EXAMPLE

FIGS. 9A and 9B are views of the multilayer ceramic capacitor 1 b of thesecond modification example as seen from the mounting surface AI2. Inthe following description, the same portions as those of the firstpreferred embodiment are denoted by the same reference numerals.

The inner edge portion 42 of the interposer 4 of the first preferredembodiment is curved in a recessed shape. In the bonding surface AI1 ofeach interposer 4, the length L2 at the central portion in the widthdirection W in the inner edge portion 42 is the shortest, and the lengthL3 of both side regions in the width direction W in the inner edgeportion 42 is the longest.

However, the present invention is not limited thereto. As shown in FIGS.9A and 9B, the inner edge portion 42 of the interposer 4 is curvedconvexly. In the bonding surface AI1 of each interposer 4, the length L2at the central portion in the width direction W in the inner edgeportion 42 may be the longest, and the length L3 of both side regions inthe width direction W in the inner edge portion 42 may be the shortest.

In FIG. 9A, both ends of the convex inner edge portion 42 are shorterthan the length L4 of the portion extending toward the second mainsurface AC2 of the main body of the capacitor main body 1A in theexternal electrode 3.

In FIG. 9B, both ends of the convex inner edge portion 42 are longerthan the length L4 of the portion extending toward the second mainsurface AC2 of the main body of the capacitor main body 1A in theexternal electrode 3.

Also in the second modification example, similarly to the firstpreferred embodiment, the length of the inner edge portion 42 is longerthan the length in the width direction W of the multilayer body 2.Therefore, the concentration of stress caused by contact with theinterposer 4 onto the second main surface AC2 of the main body of thecapacitor main body 1A is alleviated. Therefore, it is possible toreduce the possibility of cracking of the capacitor main body 1A.

(3) THIRD MODIFICATION EXAMPLE

FIGS. 10A and 10B are view of the multilayer ceramic capacitor 1 c ofthe third modification example as seen from the mounting surface AI2. Inthe following description, the same portions as those of the firstpreferred embodiment are denoted by the same reference numerals.

The inner edge portion 42 of the interposer 4 of the first preferredembodiment is curved in a recessed shape. In the bonding surface AI1 ofeach interposer 4, the length L2 at the central portion in the widthdirection W in the inner edge portion 42 is the shortest, and the lengthL3 of both side regions in the width direction W in the inner edgeportion 42 is the longest.

However, the present invention is not limited thereto. As shown in FIGS.10A and 10B, the inner edge portion 42 of the interposer 4 may include aplurality of recessed portions 46 and convex portions 45. In FIG. 10A,both ends in the width direction W of the inner edge portion 42 areconvex portions 45. In FIG. 10B, both ends in the width direction W ofthe inner edge portion 42 are recessed portions 46. Also in the thirdmodification example, similarly to the first preferred embodiment, thelength of the inner edge portion 42 is longer than the length in thewidth direction W of the multilayer body 2. Therefore, the concentrationof stress caused by contact with the interposer 4 onto the second mainsurface AC2 of the main body of the capacitor main body 1A isalleviated. Therefore, it is possible to reduce the possibility ofcracking of the capacitor main body 1A.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A multilayer ceramic capacitor comprising: a capacitor main body including a multilayer body and external electrodes, the multilayer body including dielectric layers and internal electrode layers stacked alternately, each of the external electrodes being provided on an end surface in a length direction of the multilayer body and being connected to the internal electrode layers; and two interposers provided on one surface in a stacking direction of the capacitor main body and spaced apart from each other in the length direction; the two interposers including bonding surfaces to be bonded to the one surface of the capacitor main body, the bonding surfaces including inner edge portions which are opposite to each other, the inner edge portions each having a length longer than a length in a width direction of the multilayer body.
 2. The multilayer ceramic capacitor according to claim 1, wherein the inner edge portion of each of the bonding surfaces is curved in a recessed shape.
 3. The multilayer ceramic capacitor according to claim 1, wherein the inner edge portion of each of the bonding surfaces is curved convexly.
 4. The multilayer ceramic capacitor according to claim 1, wherein the inner edge portion of each of the bonding surfaces includes at least one convex portion and at least one recessed portion; and at least one of the convex portion or the recessed portion is provided in a plurality.
 5. The multilayer ceramic capacitor according to claim 1, wherein the bonding surfaces of the two interposers have a line symmetrical shape with respect to a straight line passing through a center in the length direction and extending in the width direction, as seen from a plane extending in the width direction and the length direction.
 6. The multilayer ceramic capacitor according to claim 1, wherein the bonding surfaces of the two interposers have a line symmetrical shape with respect to a straight line passing through a center in the width direction and extending in the length direction, as seen from a plane extending in the width direction and the length direction.
 7. The multilayer ceramic capacitor according to claim 1, wherein when defining a length of the multilayer body as L, and defining a difference between a longest portion and a shortest portion in the length direction of the bonding surface as L1, L×0.05≤L1≤L×0.40 is satisfied.
 8. The multilayer ceramic capacitor according to claim 1, wherein a relationship between a length L2 of the shortest portion and a length L3 of the longest portion in the length direction of the bonding surface is L2×1.10≤L3≤L2×1.40.
 9. The multilayer ceramic capacitor according to claim 1, wherein when defining a width in the width direction of the multilayer body as W, the length of the inner edge portion is about 1.1W or more and about 2W or less.
 10. The multilayer ceramic capacitor according to claim 1, wherein the multilayer ceramic capacitor has a substantially rectangular parallelepiped shape.
 11. The multilayer ceramic capacitor according to claim 1, wherein the multilayer body has a dimension of about 0.2 mm or more and about 10 mm or less in the length direction, a dimension of about 0.1 mm or more and about 10 mm or less in the width direction, and a dimension of about 0.1 mm or more and about 5 mm or less in the stacking direction.
 12. The multilayer ceramic capacitor according to claim 1, wherein the multilayer body includes side gap portions on both sides thereof.
 13. The multilayer ceramic capacitor according to claim 1, wherein the two interposers have a same shape.
 14. The multilayer ceramic capacitor according to claim 1, wherein at least one of the two interposers includes an intermetallic compound and a single Sn metal.
 15. The multilayer ceramic capacitor according to claim 1, wherein at least one of the two interposers has a constant or substantially constant cross-sectional shape.
 16. The multilayer ceramic capacitor according to claim 1, wherein one of the external electrodes is exposed from one of the inner edge portions of one of the bonding surfaces.
 17. The multilayer ceramic capacitor according to claim 1, wherein a length of the inner edge portion of one of the interposers is longer than a width of the multilayer body.
 18. The multilayer ceramic capacitor according to claim 3, wherein a length of a central portion in the width direction in the inner edge portion is longest and a length of side regions in the width direction in the inner edge portion is shortest.
 19. The multilayer ceramic capacitor according to claim 2, wherein a length of a central portion in the width direction in the inner edge portion is shortest and a length of side regions in the width direction in the inner edge portion is longest.
 20. The multilayer ceramic capacitor according to claim 1, wherein the inner edge portion of at least one of the two interposers includes recessed portions and convex portions. 